I’ve never heard of this and I was an Ethereum miner. We pushed the cards as hard as they would go and they seemed fine after. As long as the fan was still going they were good.
I think it was about 15 years back they stopped saying that. Once we passed the 28nm mark it started to become apparent that they couldnt really state that.
It makes sense, as parts get smaller they will get more fragile from general usage.
With your GPUs yeah they are probably still fine but they could already be half way through their life time, you wouldnt know it until failure point. Add in the silicon lotto and it gets more complicated.
I design chips in modern tech nodes (currently using 2nm). What we get feom the fab is a statistical model of device failure modes. Aging is one of them. When transistors gradually age they get slower sue to increased threshold voltage. This eventually causes failure at a point where timing is tight. When will it happen varies greatly sue to initial conditions, exact conditions the chip was in(temp, vdd, number of on-off cycles, even the workload). After an agong failure the chip will still work if the clock freq is reduced. There are aging monitors on-chip sometimes which try to catch it early and scale down the clock.
There are catastrophic failures too, like gate insulator breakdown, electromigration or mechanical failures of IO interconnect. The last one is orders of magnitude more likely than anything else these days.
For graphics, the same defect could be severe enough to completely render the GPU useless.